2010/07/12 ap-1000 dcd review - oi-911-08 · 2012-12-03 · 1 ap1000dcdfilenpem resource from:...

1

AP1000DCDFileNPEm Resource

From: Altmayer, Scott A [[email protected]]Sent: Monday, July 12, 2010 5:08 PMTo: Buckberg, PerryCc: Loza, Paul G.; Melton, Michael ASubject: OI-911-08Attachments: OI-SRP9.1.1-SRSB-08 R2B-saa.pdf; OI-SRP9.1.1-SRSB-08 R2B Annotated DCD

Pages.PDF

Perry, Here is the rough draft of a revised OI question that I believe you and I agreed should be clarified and answer based on our visits, telecoms, review of other RAI details, criticality references, and some other DCD clean-up items. Please confirm the question and answers cover the type and level of information NRC needs to close this issue as we had discussed. I trust that the proposed DCD clarifications are clear and concise. Pending your feedback or discussion, I'll modify the rough draft OI and resend to NRC and NuStart for draft review. Please confirm. Thank you. ‐‐SCOTT ALTMAYER‐‐ AP1000 Licensing and Customer Interface Ph: 412‐374‐6079 Cell: 440‐289‐0624

Hearing Identifier: AP1000_DCD_Review Email Number: 490 Mail Envelope Properties (EF1E2C8A89BEC84D80BBDC48E17396EEE8E88B8F) Subject: OI-911-08 Sent Date: 7/12/2010 5:07:38 PM Received Date: 7/12/2010 5:07:48 PM From: Altmayer, Scott A Created By: [email protected] Recipients: "Loza, Paul G." <[email protected]> Tracking Status: None "Melton, Michael A" <[email protected]> Tracking Status: None "Buckberg, Perry" <[email protected]> Tracking Status: None Post Office: SWEC9980.w-intra.net Files Size Date & Time MESSAGE 737 7/12/2010 5:07:48 PM OI-SRP9.1.1-SRSB-08 R2B-saa.pdf 132839 OI-SRP9.1.1-SRSB-08 R2B Annotated DCD Pages.PDF 945180 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received:

AP1000 TECHNICAL REPORT REVIEW

Response to Open Item (OI)

OI-SRP9.1.1-SRSB-08R2B

Page 1 of 8

RAI Response Number: OI-SRP9.1.1-SRSB-08 Revision: 2B

Question: Spent Fuel Criticality Analysis

(Revision 0 and 1)

Based on the review of the TR65 (Revision 1) criticality analysis methodology and its application, the NRC staff questioned the applicant’s burnup credit assumption that a 5% reactivity uncertainty penalty included the effects of missing nuclide data on the computational biases and uncertainties. This issue was raised in RAI-SRP9.1.1-SRSB-08.

In response to this 5% burnup uncertainty concern by the NRC, the applicant’s September 16, 2009 letter described a loading pattern restriction on the Region 2 racks and the applicant’s plan to submit a simplified analysis that does not require burnup credit (or which will remove or preclude the need for using burnup credit). This plan will not require any changes to the physical rack design as presented in TR-65. Evaluation of this restricted loading pattern, corresponding analyses, and Technical Specification changes related to this restricted loading pattern are tracked by OI-SRP9.1.1-SRSB-08.

New Question: (Revision 2B)

Additional review of the updated Chapter 9 SER proprietary clarifications from Westinghouse, review of various RAI and DCD changes noted in RAI-SRP9.1.1-SRSB-05 to support the criticality methodology for spent fuel storage, redesign of the spent fuel pool racks, and completion of the spent fuel pool and new fuel pit seismic/structural audit action items has occurred. NRC believes additional clarification and changes are needed to the DCD to clarify, correct, and complete statements regarding new fuel rack and spent fuel rack criticality.

Westinghouse Response

(Revision 0 and 1):

This SER Open Item (OI) response completes the three tasks noted below:

1) It clarifies Westinghouse’s intent to retain and license a full-capacity spent fuel pool. This clarification is based on a criticality analysis that meets the requirements of both 10 CFR 50.68, and the current guidelines established by the NRC, regarding how to account for burnup uncertainties. The Westinghouse response, technical approach, and revised criticality analysis (i.e. APP-GW-GLR-029 (TR65), Rev. 2) to satisfactorily address the NRC concerns regarding the 5% burnup credit assumption noted above, are stated in the response to RAI-SRP9.1.1-SRSB-08 (Reference 1). The DCD changes describing the full-capacity spent fuel pool (SFP) were submitted in response to RAI-SRP9.1.1-SRSB-05 (Reference 4). These




Page 2 of 8

two RAIs and the supporting criticality analysis are requested to be approved by the NRC for use in the pending AP1000DCD amendment.

2) It retracts the Westinghouse proposal noted in the September 16, 2009 letter (Reference 2)that suggested a restricted loading pattern (i.e. checkerboard pattern) would be pursued as the primary criticality safety basis for the SFP. That letter proposed to submit an alternate conservative SFP criticality analysis that takes no credit for fuel depletion or burnup. This checkerboard pattern would have imposed an adverse loading restriction on the Region 2 racks by reducing the spent fuel storage capacity by over 300 cells. Westinghouse chose not to exercise this proposal and did not describe or submit details of the checkerboard pattern or analysis to NRC.

3) It explicitly requests NRC to evaluate, review, and approve the backup checkerboard pattern and criticality analysis in calendar year 2010 to support the potential future use of this restricted loading pattern for the AP1000 SFP. This backup approach uses a new methodology that meets 10 CFR 50.68, does not use or reference WCAP 14416-NP-A, and does not credit soluble boron or fuel assembly burnup for subcriticality control in the Region 2 spent fuel racks. This backup checkerboard approach and criticality analysis is described in Westinghouse calculation APP-FS02-N1C-003, Rev. 0 (Reference 3). A proprietary version of this calculation is being submitted by separate letter to the NRC for review and audit, as applicable.

Westinghouse considers this checkerboard approach to be a proactive contingency for potential future use and operational flexibility of the AP1000 SFP if more restrictive decisions or guidelines regarding burnup credit uncertainties are imposed by the NRC in the future during the AP1000 rulemaking process. The intent of submitting this checkerboard pattern for approval is to provide a contingency for use by Westinghouse and the NRC that confirms the AP1000 SFP design remains safe and licensable relative to nuclear criticality.

New Response: (Revision 2B)

During telecoms and finalization efforts, Westinghouse and NRC have identified additional DCD changes that will clarify, correct, and/or complete statements regarding new fuel rack and spent fuel rack criticality, references, and dimensioning. These additional changes are conforming in nature and are supported by existing calculations, RAI responses, design changes, and/or errata to correct grammatical anomalies. They will assure consistency and completeness of the DCD.

The summary of proposed DCD changes and bases are shown in the table below; and are additions to those DCD changes already completed and processed. The table precedes the annotated DCD pages attached to the “DCD changes” section of this RAI.




Page 3 of 8

Reference(s):

1) Westinghouse Letter DCP/NRC_002735, 1/8/10, re: response to RAI-SRP9.1.1-SRSB-08

2) Westinghouse Letter DCP/NRC_002619, 9/16/09, re: alternate restricted loading pattern for spent fuel pool to show 10 CFR 50.68 compliance

3) APP-FS02-N1C-003, Rev. 0, January 2009, “AP1000 Spent Fuel Pool Criticality Analysis without Credit for Soluble Boron or Assembly Burnup” (Proprietary)

4) Westinghouse Letter DCP/NRC_002511, 5/29/09, re: response to RAI-SRP9.1.1-SRSB-05 (contains DCD markups that support criticality analysis for full-capacity SFP loading)




Page 4 of 8

Design Control Document (DCD) Revision:

DCD Changes: (Revision 0, 1)

The DCD changes describing the full-capacity SFP are identified in the response to RAI-SRP9.1.1-SRSB-05 (Reference 4). These DCD changes remain applicable to this response.

If the backup restricted-loading checkerboard pattern and criticality analysis are needed for use in the future, appropriate DCD changes, ISG-11 notifications, and applicable processes will be completed and submitted to the NRC at that time.

DCD Changes: (Revision 2B)

See attached summary table and annotated DCD mark-up pages.

PRA Revision: None.

Technical Report (TR) Revision: None.




Page 5 of 8

Summary of Proposed DCD Changes Regarding Nuclear Criticality

TOPIC(DCD Section)

Location(Sect., Page,Para., Line)

Change Description Change Basis

Tier 1, ITAAC

2.1.1, Fuel Handling and Refueling System

2.1.1,pg. 2.1.1-1 Item 7

Clarify criticality evaluation acceptance criteria by adding Code 10 CFR 50.68 reference and note. (ref. RAI-SRP9.1.1-SRSB-05)

Explain

Table 2.1.1-1, pg. 2.1.1-3 Item 7, Acceptance Criteria

Clarify criticality evaluation acceptance criteria by adding Code 10 CFR 50.68 reference and note. (ref. RAI-SRP9.1.1-SRSB-05)

Explain

4.3.2.6.1, Criticality Design Method Outside the Reactor

4.3.2.6.1,pg. 4.3-29

Add last sentence to state where new fuel rack and spent fuel rack criticality methods are addressed. (See Insert #1)

Simplify

Table 4.3-4, pg. 4.3-51

Delete table. New benchmark critical experiments exist for spent fuel racks criticality that supercede those listed in the table. (ref. RAI-SRP9.1.1-SRSB-05)

Correction

New Fuel Racks

9.1.1.1, Design Bases

9.1.1.1,pg. 9.1-1,Para. 2, Line 6-7

Remove duplicate statement on assembly insertion to a full location. Carried from AP600.

Simplify

9.1.1.3, Safety Evaluation

9.1.1.3,pg. 9.1-5,Para. 3, Line 1

Change last sentence to include new fuel rack and directly state Reference 17

Simplify

Spent Fuel Racks

9.1.2.1, Design Bases

9.1.2.1,Pg. 9.1-5,Para. 2, Line 2

Remove duplicate statement on assembly insertion to a full location. Carried from AP600.

Simplify




Page 6 of 8

9.1.2.3, Safety Evaluation

9.1.2.3,pg. 9.1-11, Para. 5, Line 2

Change last sentence to include spent fuel rack and directly state Reference 20

Simplify

9.1.7, References 9.1.7,pg. 9.1-50

Show Reference 20 as “(Proprietary)”(ref. RAI-SRP9.1.1-SRSB-05)

Correction

Tech Specs

Tech Spec Design Features, 4.3, Fuel Storage

4.3.1.1.c,pg. 4.0 - 2, Lines 1 and 2

Change “10.90” to “10.93” and“9.028” to 9.04”(ref. RAI-SRP9.1.2-SRSB-06)

Correction

Tech Spec BASES 3.7.11, Fuel Storage Pool Boron Concentration

pg. B 3.7.11-3,Reference 3

Change “critically” to “criticality” Correction

Tech Spec BASES 3.7.12, Spent Fuel Pool Storage

pg. B 3.7.12-2, Background (cont’d),Line 4-5

Typo from DCD Rev. 16. Correct the partial sentences to match the misplaced fuel accident described in B 3.7.11, “Background” (pg. B 3.7.11-1). (See Insert #2)

Correction

pg. B 3.7.12-3,Actions,Para. 1, Line 3, Para. 2, Line 3

Change “Region 2 or 3” to “Region 2”(ref. RAI-SRP9.1.1-SRSB-05)

Correction

pg. B 3.7.12-4,SurveillanceRequirements, Para. 1, Line 7

Add “…or the Defective Fuel Cells” commensurate with flexibility in Action A.1 and LCO 3.7.12 that this is an acceptable storage location. Consistent with other DCD changes. (ref. RAI-SRP9.1.1-SRSB-05)

Correction




Page 7 of 8

Insert #1

Insert #1 (to 4.3.2.6.1, Criticality Design Method Outside the Reactor): Add sentence below after first paragraph to state where new fuel rack and spent fuel rack criticality methods are addressed.

“The details of the methodology used for the new fuel rack and spent fuel rack criticality analysis are included in the Chapter 9.1 references.”

Insert #2

Insert #2 (pg. B 3.7.12-2, Background (cont’d), copied from B 3.7.11, Background: Clarify accident described in Line 4-5 by replacing with sentences below.

“For example, the only accident scenario that has the potential for more than negligible positive reactivity effect is an inadvertent misplacement of a new fuel assembly. This accident has the potential for exceeding the limiting reactivity, should there be a concurrent and independent accident condition resulting in the loss of all soluble poison.”




Page 8 of 8

Annotated DCD Changes

OI-SRP9.1.1-SRSB-08 (Revision 2B)

(Cover plus 15 pages)

2010/07/12 ap-1000 dcd review - oi-911-08 · 2012-12-03 · 1 ap1000dcdfilenpem resource from:...

Documents